1. Field of the Invention
The present invention relates to a storage medium having a game program stored therein, a game apparatus, a game system, and a game processing method, and more particularly, to a storage medium having a game program stored therein, a game apparatus, a game system, and a game processing method, which are capable of performing a predetermined game processing based on a biological signal obtained from a player.
2. Description of the Background Art
Conventionally, for example, Japanese Laid-Open Patent Publication No. 10-024172 (hereinafter referred to as Patent Document 1) discloses a game which is performed based on heartbeat data obtained from a heartbeat detector that a player wears. In a game machine disclosed in Patent Document 1, the color of the face of a character controlled by the player is changed, or the size of the arm or fist of the character is changed, based on the heartbeat data obtained from the player.
In order to obtain a biological parameter such as the heartbeat or pulse of a player, it is necessary to continuously obtain a biological signal indicating such as a pulse wave directly obtained from the player, and calculate the biological parameter based on the continuously obtained biological signal. That is, when the biological parameter is calculated based on the biological signal continuously obtained from the player per unit time and game processing is performed based on the calculated biological parameter, a certain amount of time is required until the biological signal obtained from the player is reflected to the game processing. The game machine disclosed in Patent Document 1 performs, based on the biological parameter, game processing in which the timing of changing the color of the face of the character controlled by the player or the timing of changing the size of the arm or fist of the character is not required to be very precise. Accordingly, in the game machine disclosed in Patent Document 1, even if a time lag occurs between when the game machine starts to obtain the biological signal and when it starts to obtain the biological parameter, such a time lag does not cause a serious problem. However, when performing game processing in which the timing to control an object must be precise, such a time lag may cause a deterioration in responsiveness, and thus precise control cannot be realized.